Overload-circuit breaker



Dec. 26, 1922. 1,439,692; C. B. COATES.

OVERLOAD CIRCUIT BREAKER.

oruGm/u. msn MAY 1. 1920. 2 SHEETS-sain x..

Dec. 26, 1922. 1,439,692,

xc. B. COMES.

OVERLOAD CIRCUI BREAVKVER.

omGML mw MAY 1. 192o. 2 SHEETS-SHEET 2.

solenoid is also provided with an Patented Dec. `26, 1922.

' 1,439,692 PATENT OFFICE.

CHARLES B. COATES, 0F ERIE, PENNSYLVANIA, ASSIGNOR TO CHICAGO PNEUMATICTOOL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY. l

OVEBLOAD-CIRCUIT BREAKER.

Original application led Hay 7, 1920,` Serial No. 379,460. Divided andthis application led March 14,

To azZZ who/m. t may concern:

Be it known that I, CHARLES B. COATES, a citizen of the United States,now residing at Erie, in the county of Erie and State of Pennsylvania,formerlyI residing at New York, in the county of of New York, haveinvented certain new and useful .Improvements in Overload-CircuitBreakers, of which the following is a specification, this applicationbeing divisional of an original application filed on May 7, 1920, SerialNo. 379,460. l

M invention relates to what are known as overload circuit breakersadapted for use with tools, for instance with portable electric drillsand the like wherein it becomes necessary to break the circuit in theevent that the drill bit should stick or otherwise be given an overload.The object ofy my invention is to provide a novel and eiiicient'construction of arc extinguisher or blowout for a circuit breaker ofthis character.

In the drawings Fig. 1 is a side elevation of my circuit breaker; Fig. 2an end elevation thereof viewed from the line 2 2 of Fig. 1 and lookingin Athe direction of the arrow; Fig. 3 a erspective of a detail of thecontact base; ig. 4 a sectional plan of the switch mechanismtaken on theirregular line 4-4 of Fig. 5; and Fig. 5 a" sectlonal elevation on theline 5-5 of Fig. 2.

Referring to the particular embodiment of my invention which is hereinshown for the purpose of a clear and definitev description but which maypartake of different forms, the mechanism is mounted on and supported byan angle iron framework 1 carrying a base 41 of insulating material.Themech'anism comprises essentially a solenoid and switch mechanismtogether with a dashpot arrangement for controlling the movements of thesolenoid core or plunger. This solenoid is preferably of the stoppediron clad type consistin of the casing or frame 2, series coil 3 an coreor plunger 4. This solenoid is secured to the brackets 5 which in turnare secured to the frame work 1. The

6 which extends into the core opening of the coil and is secured toanend disk or plate 7 inesuitable manner as by screwing thereinto. Thisplug has a centralA bore in fwhich slides by a nice sliding fit a rod 8which is made of suitabilenon-magnetic materialsuch as brass,

ew York and Statev iron plug 'which llimits the outward .plate 28 andits plunger 4. Upon the outer 1921. Serial No. 452,162.

This rod is unattached at'either end but is adapted to contact at itsright hand end the plunger 4 and at its left hand end the dashpot deviceas hereinafter explained.

The dashpot device is contained within a casing 9 secured in suitablemanner to the casing or frame 2 of the solenoid as by screwing thereintoand locked in place by means of set screw 10. Within this case there islocated a cylinder 11 which provides a dashpot chamber 12. A portion ofthe interior of the casing 9 is of larger diameter than the cylinder 11with the result that an annular chamber 13 is formed therebetween. Thisannular space or chamber communi- Cates with the dashpot chamber 12through the rearward ports 14 and a forward port 15 which is locatedintermediate the length of the cylinder 11. b

Within the cylinder 11 there reciprocates a piston 16 which has atubular stem 17 adapted to communicate with opposite sides of the pistonthrough the ports and passages `18 and the port 19 passing through adisk 20 in the left hand end of such stem. The ports and passages 18 aregoverned by means 'of a check valve within the stem, which vits 'outerend against the flat face of the piston 16 and is adapted to force suchpiston outwardly to the left when lactuated by means of the plunger 4 inthe manner hereinafter explained.

Referring to the anism which is actuated by the plunger 4, the sameconsists of a bolt 26 secured to the projecting end of the plu-nger insuitable manner asv by screwing thereinto and clamping between the endqthereof and a nut 27 a plate 28 whose upper end is notched in order toreceive the lower edge of a bracket or guide 29 which is secured to .andprojects forwardly of the right end of the casing 2. This bracket isprovided with a'fiange 30 movement of the switch controlling mecliscrewthreaded end of the bolt 26 there is mounted two similar adjustable nuts31 clamping between them a dog .32 separated therefrom by suitableinsulating materlal 33. 4This dog projects downwardly and 1s therebyenabled to actuate the switch and its operating means nowv to bedescrlbed. I

My switch is of novel constructlon particularly as to the contacts whichhere consist of three rollers on the one side and two seats or saddles.and -interposed spring; Two of these rollers 34, 34 are of the samediameter but the third roller35 which is interposed between them is ofsomewhat greater diam-V eter. These rollers are all mounted upon ahorizontal rod 36 connecting the outer ends of a yoke or substantiallyrectangular frame' which is composed of two parallel bell cranks havinglongv arms 37 and short upright arms 38. These bell cranks are ivotedupon ythe rod 39 at the-upper en /of the standard 40 which is secured tothe base or support 41. The upper endsof the bell crank arms 38 areconnected by the cross rod 42. These rollers and their yoke are held tothe normal downward position shown in Fig. 5 by suitable means such asthe spring 43.

These rollers 34 and 35 constitute switch contacts that are adapted tocooperate with other switch contacts which consist of the saddles 44cooperating with the smaller rollers 34 and with a spring 45 made ofsuitable material such as bronze or nonarcing material. This spring issecured at its outer end to the plate 46 and its inner end projectsforwardly between the two saddles 44 in position tol be contacted by thelarger roller 35. The construction and arrangement of these parts aresuch that the larger roller 35 does not' leave its contact or spring 45until after the smaller rollers 34 have left their seats in the saddles44 with the result that the current passes through the larger roller andthrough its spring when such current is finally broken, and is notthenpassing through the smaller rollers, so that the seats in thesaddles for the smaller rollers are always bright and unaffected by anyarcing action and therefore always in suitable conditions for' 4carryingthe current in service. It will be understood that the rollers and thesaddles and the spring are connected to the electrical ,supply wires.A

A shunt coil 47 is provided for the magnetic blowout and for holding thecircuit breaker device in open switch position. One end of this coilisconnected to the spring 45 and the other end tothe base 40 so thatcurrent flows through it only when the switch is in the open position.This coil is mounted at the upper end of two uprights or stand ards ormagnetic yokes 48 which are suitably mounted. This coil cooperates witha pair of magnetic poles 49 which in turn are adapted to attract andhold an iron armai'aaaeca ture "50"mounted upon the switch breaker.device or frame, 37. A pair of magnetlc plugs 51 are secured in thebrackets 52 which yare a part of the casting containing the saddles 44and positioned with their arc gap in the lin'e of possible arc betweenthe`roller 35 and itsspring 45 so as to blowout any such arc. lnthisconstruction these plugs 51 constitute the horns of the magnet andare placed ver close to the roller 35 and 'its spring an moreover theyhave the same electrlcal polarity as these parts when they are incontact, and lthe same as the spring 45 after the circuit is opened.This is made possible by using electrical insulation 53 between theplugs 51 and the The advantage of this construction is to provide -avery short air gap through the arc and obtain an intense ield forblowing .out such arc.v .y

Describing a cycle of operation of my circuit breaker and starting withthe parts in their normal position shown in the drawings, when the toolsuch as an electric drill is started from a state of rest there is amomentary rush of c'urrentffar in excess of the safe normal runningcurrent. The sudden and intense inward pull onthe plun er 4 due to thehigh current passing throng the coil 3 is opposed by the dashpot. Thlscurrent is of extremely short duration and the port 15 is so placedthat' it is not uncovered by the'piston 16 during this rush of startingcurrent. After the drill has been started and is running without loadthe plunger 4 and dashpot 16 assume the positions shown in the drawings.When the drill is materimagnet yokes 48.

ally slowed down or stopped as by -reason of" the sticking of the drillbit the working current will increase in the solenoid with the resultthat the plunger will be moved to the left in Fig. 5 and consequentlythe piston 16 will be likewise moved by reason of the interposed rod 8.Inasmuch as the chamber 12 isa closed one this movement of the pistonwill "cause a compression of the air to the left of such pistonv therebyopposing themovement of said plunger. When the strai ht side or righthand face of the piston16 as moved sufficiently to the left to uncoverthe port 15 the annular chamber 13 will act as a bypass and the pressureof lthe air on opposite sides of the piston will be equalized whereu onthere will be no further resistance o ered to the movement of theplunger,"

cross rod 42 which together with the movf` able members of the switchare rocked to the dotted line position shown in Fig. 5. The armature 50is now held magnetically by the poles 49 which is the open switchposition.

In this ope-ration of the switch the small rollers 34 leave their seatswhile the larger roller 35 is still in Contact with its spring andbefore it breaks contact with such spring. Moreover, the dog 32 does notstrike the cross rod 42 of the breaker device until the plunger hasmoved to that pointwhere the dashpot piston has passed thevv port 15,that is to say the cushioned movement of the plunger 4 occurs before thedog comes into contact with the rod 42 and the cushioning action isrelieved at the moment when such dog makes such contact with the rodwith the result that the rollers are 'moved out of Contact with theircontacts rapidly and with a rapid, snappy action. Afterthe current hasthus been interrupted orv cutout the spring 23 will return the pistonand the plunger.

In the solenoid an iron clad magnet is preferably employed so that whenthe current flows through the coil there is magnetic attraction betweenthe adjacent ends of the plunger 4 and the plug 6 and also between theends of the casing 2 and the plate 28.

I claim:

- l. In an overload circuit breaker, the combination of a ma eticallyoperated switch,

and a shunt coil aving magnetic poles for holding the switch in openposition, and also having magnetic poles for blowing out the arc at theswitch.

2. In an overload circuit breaker, the com- `bination of a magnetically7operated switch,

erating with said armature and having elec trically insulated poles forblowing out the. arc at the switch.

4. In an overload circuit breaker, the combination of a magneticallyoperated switch including a swinging frame carrying movable switchcontacts, an armature on said trame and a shunt coil having polescooperating with said armature and having poles for blowing out the arcat the switch, said coil having yokes and insulation between such yokesand poles.

CHARLES B. ooATEs.

